build(deps): bump readchar from 4.1.0 to 4.2.0

Bumps [readchar](https://github.com/magmax/python-readchar) from 4.1.0 to 4.2.0.
- [Release notes](https://github.com/magmax/python-readchar/releases)
- [Commits](magmax/python-readchar@v4.1.0...v4.2.0)

---
updated-dependencies:
- dependency-name: readchar
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>